Senior man with young bride © PNC, Brand X Pictures, Getty Images

Two daughters appealed to elder-law attorney Shirley Whitenack of Florham Park, N.J., for help. Their father had written a $10,000 check to a caregiver at his nursing home.

A psychiatrist whom Whitenack hired to assess the father found him to be competent. The elderly gentleman knew that the checks represented a small portion of his multimillion-dollar net worth and that he could easily afford the generosity.

The nursing home wasn't so forgiving. It fired the caretaker for taking the gift. And then things took a horrible turn: The father married the caretaker, who used her newly acquired access to his bank accounts to clean him out.

"She took the money and went to Antigua," Whitenack said. "She left Dad stranded."

Protecting our elderly parents from people who may want to victimize them financially isn't easy. Moms or dads may interpret our concern as self-interest. Sometimes it is. Other times we see what they can't or won't: that people who profess to care about them really don't or are so flawed that they present a risk to the parent's well-being.

"It's so common, especially in the caregiving world," said Geraldine Champion, an elder-law attorney in San Luis Obispo, Calif.

Champion represented the family of a 56-year-old stroke victim whose 75-year-old caretaker gave him Viagra and proposed marriage. The caretaker wanted to move the severely disabled man from his assisted-living facility, where he needed 24-hour care, to his oceanfront home, where she promised to care for him all by herself. After the family intervened, the caretaker moved away. The woman who once professed her undying love sent "one measly card" afterward and hasn't called or otherwise contacted him since, Champion said.

Liz Weston

Liz Weston

The worst of these romantic predators are known in retiree communities as black widows or black widowers, after the mate-eating spiders. Elder-law experts say black widows and black widowers can run the gamut from mere opportunists to calculating criminals who move from victim to victim. They either take control of retirees' finances or persuade the seniors to give them money and property, sometimes leaving their victims penniless.

Terrie McKinley of Orange County, Calif., was happy at first when her mom, then 76, started seeing an old schoolmate that the older woman ran into at a high school reunion. After the man moved in with her mom, though, he became hostile to McKinley and her family. He convinced the mother that she couldn't trust her daughter.

McKinley's name was removed from her mother's accounts, which McKinley had managed, and the older couple changed the locks on the condo where they lived.

McKinley worried when she learned her mother, who was in the early stages of dementia, was being left home alone while her partner went on days-long trips. Unexplained bruises began showing up on her face and arms. McKinley said she asked the county's social-services agency to investigate, but no wrongdoing was found.

The man conned the couple's neighbors into believing that McKinley was the abusive, money-grubbing one. Some of the neighbors confronted McKinley when she visited her mother's condo. McKinley seethed with embarrassment and frustration.

"They were saying, 'How dare you -- he's a nice old man,'" McKinley remembered. "(Joseph) Mengele died an old man. Charles Manson is an old man. Just because you're old doesn't mean you're nice."

One night, her mother broke her leg in two places. The hospital doctors discovered she was suffering from malnutrition, and McKinley learned that her mom's life savings -- $150,000 -- had vanished. The money that should have lasted the rest of the woman's life "was gone in six years," McKinley said.

What was especially painful, McKinley said, was that her mother got so little benefit.

"She didn't take cruises or buy nice things," McKinley said. "She was wearing rags and sitting on her sofa alone, while this clever old fool was dressed to the nines and running all over town on her money."

Other times it can be hard for families to tell if they're dealing with a predator or a real paramour. The kids' judgment can be clouded when they realize Dad's girlfriend may one day stand between them and an inheritance.